It is known that frequently in supermarkets devices are placed for dispensing plastic bags, having the object of helping the operators and/or the customers in inserting into said bags the items purchased at the supermarket. There are also known bag opening devices which are incorporated in the supermarket check-out counters. Devices of this kind are described for example in the U.S. Pat. No. 4,085,822 and in U.K. Patent Appln. No. 2,055,084.
Moreover, it has been recently invented, and forms the object of the Italian Patent Appln. No. 2455 A/89 of the same Applicant, an integrated machine suitable to be incorporated in a supermarket checkout counter, which automatically dispenses the plastic bags one at a time from a continuous strip of bags, opens them underneath a suitable mouth located on the counter upper surface, and unloads them after they have been filled.
All the above mentioned prior art apparatus and machines comprise a device for opening the plastic bags one at a time, and for keeping them open as long as they are filled by the customer and/or the check-out counter operator. Such known devices, though very functional and reliable, are not without inconveniences, such as jamming, tearing of the bag edges, and so on.
It is therefore an object of the present invention to provide a device, free from these inconveniences for automatically opening the bags and keeping them firmly in an open position as they are being filled.
This object is attained by a device comprising two pliers capable of horizontal reciprocating motion on motor-driven guides which grasp and open the two opposite sides of a bag fed by conveyor belts. Each pliers consists of two jaws hinged at the guides and pushed against each other by a spring interposed between at their ends. One end of each pliers is provided with a roller suitable to interact with a device that opens and closes the pliers.
The bag opening device according to the present invention has the advantage of having a very simple structure, and therefore maximum reliability. Another advantage of the bag opening device according to the present invention is of an economic nature, since its simple structure requires reduced manufacturing costs.